Laparoscopy is one example of a microinvasive medical method. By means of a trocar, an artificial access route to the abdominal cavity of a patient is created through the abdominal wall. Through the lumen of a tube of the trocar that remains in the abdominal wall during the laparoscopic intervention, it is possible for an endoscope and/or other medical instruments (for example forceps, scissors, needle holders) to be inserted into the abdominal cavity. During the laparoscopy, the abdominal space is filled carbon dioxide or another gas in order to create a pneumoperitoneum, a hollow space permitting the medical intervention. Without special measures, this gas would escape through the lumen of the tube of the trocar. Therefore, numerous solutions were developed with the aim of closing the lumen of the tube of a trocar in a manner that is as fluid-tight as possible, specifically both in the empty state and also with an instrument inserted. Partially similar problems may arise in a work channel of an endoscope or when inserting a catheter into a blood vessel. In the latter case, however, it is not the escape of gas that is to be prevented, but the escape of blood.
U.S. Pat. No. 4,857,062 describes a valve for inserting a catheter into an artery. For sealing purposes, a duckbill-shaped first element is provided, and a second flexible element which is compressed by a catheter in order to form a fluid-tight seal. Both elements are arranged one behind the other and rigidly in a housing.
WO 93/01850 A1 describes a lever-actuated seal for a tube. A wall made of an elastomer and having an opening is expanded by several levers during the insertion of an instrument into the tube, as a result of which the opening is enlarged.
U.S. Pat. No. 5,366,446 describes an introducer assembly for use on the skin of a patient, said assembly being designed for the insertion of tubes with different external diameters. The assembly comprises a membrane made of a pierceable elastomer material and arranged in the center of a bellows.
EP 0 630 660 A1 describes a seal assembly for accommodating a surgical instrument. The seal assembly comprises a duckbill seal or an arrangement composed of a plurality of sealing elements which are partially slit in a star shape and which partially overlap one another and are partially conical.
EP 0 746 359 B1 describes a catheter check valve. For sealing purposes, a rubber seal with an aperture is provided and, in the distal direction from this, a duckbill valve with a rectilinear slit.
WO 2010/045702 A1 describes a disposable seal for a tube, The disposable seal has an approximately cup-shaped design with intersecting slits at the base.
U.S. Pat. No. 4,430,081 describes a cannula for use with angiography catheters. To provide a seal against the entry of air or against the escape of blood from a blood vessel, a first seal with a slit, a second seal with a hole, and a third seal with a flapper in it are provided, which seals are arranged adjoining one another.
WO 91/12838 A1 proposes an infusion port with a plurality of elastic disks which are arranged one after another and which each have circular openings or have star-shaped slits offset in rotation relative to one another.
EP 0 536 549 A1 describes a trocar sleeve for the passage of a medical instrument. A sealing device for sealing an axial passage and a hollow shank, both when an instrument is inserted and also when an instrument is not inserted, comprises one or more partition walls made of elastic material with intersecting slits offset relative to each other.
WO 94/01149 A1 and DE 693 29 286 T2 describe a valve for an introducer assembly. A body made of silicone or of another elastomer material comprises a cylindrical wall, which encloses a bore. One end of the cylindrical wall and of the bore is closed by a wall with a centrally arranged opening. The other end of the cylindrical wall and of the bore is closed by two mutually inclined leaflets with a slit lying between them.
WO 98/32484 A1 describes catheter insertion equipment with a hemostatic valve. A sealing element comprises two holed support disks, between which is provided a sealing disk made of a soft, elastic foam plastic with radially extending slits.
EP 1 269 925 A1 describes an access cannula for endoscopic operations. A twin-disk valve comprises two disks, each of them with a star-shaped slit with three arms, wherein the slits of the two disks are offset in rotation relative to each other.
EP 1 350 476 A1 describes a trocar sleeve with a valve. The valve comprises an insertion region with angled wall sections running toward each other in the distal direction, and with sealing lips lying elastically against each other.
The described sealing devices each have specific advantages and disadvantages. For many fields of use, satisfactory solutions have not yet been found, or at least further improvements are desirable. This is particularly the case in view of the fact that a sealing device is intended to satisfy numerous requirements simultaneously. For example, the sealing device should be fluid-tight, robust, re-usable and in particular autoclavable, should offer the least possible resistance to a movement of a medical instrument in the axial direction, should permit lever manipulation or tilting of a medical instrument inserted into the sealing device and also remain fluid-tight, should not turn inside out either during the insertion or during the removal of a medical instrument, and should be able to be produced cost-effectively.